Gremio striker Luan Guilherme de Jesus Viera has emerged as the new top candidate to bolster the Barcelona attack, according to Sport. The 23-year-old forward was heavily linked with a move to Leicester City earlier in July but after the deal to the Premier League giants didn't go ahead it looks that his destiny could be at the Nou Camp.

Barcelona have earmarked the signing of a forward as a priority for the current transfer window as Luis Enrique wants a player to back-up the MSN trio formed by Lionel Messi, Luis Suarez and Neymar.

However, the La Liga champions have failed to convince their top targets to join them amid concerns that the new signing will struggle to secure for regular time, as it was the case of Pedro Rodriguez or Alexis Sanchez before the current Premier League duo opted to make the move to Chelsea and Arsenal respectively.

Kévin Gameiro, Tony Sanabria, Nolito, Hatem Ben Arfa, Ousmane Dembélé and especially Sevilla new signing Luciano Vietto have been linked with Barcelona in recent months, but all have eventually moved to other clubs.

Barcelona director of professional sports Albert Soler revealed on Friday that the club had been forced to activate a new back-up plan, with club technical secretary Robert Fernandez making a desperate trip to South America to secure the services of a promising striker.

Luan could serve as a back-up for Lionel Messi, Luis Suarez and Neymar at Barcelona.Getty

"We are looking for a young forward (of around) 22-years-old", Soler said as quoted by Sport. "The technical secretary, Robert Fernandez, has travelled to South America. We are following some players there who have been in our agenda for some time. We would like to present him in the Gamper. But it is true that we have time until 31 August.

"The objective is that he is here for the start of La Liga [21 August]. If we can close the deal in 15 days, we will do. There are various open negotiations and one of the conditions that we want is that the player wants to come to FC Barcelona."

Sport now claims that coveted Gabriel Jesus was the top priority but Barcelona have been finally been forced to turned their attention to his compatriot Luan as the former is expected to move to Manchester City instead.

Luan is also set to represent his country in the Rio 2012 Olympics along Gabriel Jesus himself, Neymar or Gabriel Barbosa Gabigol, who has also been linked with the Catalans in the past.

The striker is considered as one of the most talented players to emerge from the Gremio academy, who in recent seasons have overseen the irruption of some major stars like Ronaldinho, Douglas Costa or former Manchester United's Anderson.

Earlier in July his agent told ESPN that he was in negotiations for the number nine to move to Leicester. However, the move to the King Power Stadium looks to have been frozen since the Premier League champions signed Ahmed Musa from CSKA Moscow.

Sport claims that Luan is still likely to make the move to Europe and would accept to be an understudy at Barcelona.

Meanwhile, according to the reports, Gremio would let him go for around €20m (£16.9m, £22.3m), a reasonable fee for Barcelona after the club's economic vice-president, Susana Monje, recently revealed that they still have around €24m left in the kitty to sign a striker.

Barcelona, nevertheless, are also monitoring other alternatives in the European football, with Newcastle's Ayoze Pérez, Lucas Pérez, Mario Gómez and Carlos Bacca among the potential candidates linked in recent days.